Slow start of WAM after booting

After booting on the M3 board, it takes a lot of time to start WAM in order to be able run the first webapp, up to 40s. Once the first app is initialized all of them start normally.

Jul 10 18:09:14 m3ulcb systemd[1]: Started YouTube.
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: ## (DEBUG)[int main(int, const char**)] ### Starting /usr/bin/web-runtime
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: ## (DEBUG)[virtual int WebRuntimeAGL::run(int, const char**)] WebRuntimeAGL::run
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: ## (DEBUG)[virtual int WebRuntimeAGL::run(int, const char**)] WebRuntimeAGL - creating WebAppLauncherRuntime
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: ## (DEBUG)[virtual int WebAppLauncherRuntime::run(int, const char**)] WebAppLauncherRuntime::run - creating SingleBrowserProcessWebAppLauncher
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: ## (DEBUG)[bool WebAppLauncherRuntime::init()] 0: http://localhost:31043/index.html?token=HELLO
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: ## (DEBUG)[bool WebAppLauncherRuntime::init()] 1: http:
...
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: ## (DEBUG)[bool WebAppLauncherRuntime::init()] id=[webapps-youtube@1.0], name=[YouTube], role=[WebApp-31043], url=[http://localhost:31043/index.html?token=HELLO], port=31043, token=[HELLO]
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: ## (DEBUG)[void WebAppLauncherRuntime::notify_ivi_control_cb(ilmObjectType, t_ilm_uint, t_ilm_bool)] ivi layer: 100 created.
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: ## (DEBUG)[void WebAppLauncherRuntime::notify_ivi_control_cb(ilmObjectType, t_ilm_uint, t_ilm_bool)] ivi layer: 1000 created.
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: ## (DEBUG)[void WebAppLauncherRuntime::notify_ivi_control_cb(ilmObjectType, t_ilm_uint, t_ilm_bool)] ivi surface (id=1, surf_pid=3523) [m_rid:0] is created.
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: ## (DEBUG)[void WebAppLauncherRuntime::notify_ivi_control_cb(ilmObjectType, t_ilm_uint, t_ilm_bool)] ivi surface (id=2, surf_pid=3524) [m_rid:0] is created.
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: ## (DEBUG)[virtual int WebAppLauncherRuntime::run(int, const char**)] waiting for notification: surface created
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: ## (DEBUG)[void WebAppManagerServiceAGL::triggerStartupApp()] Triggering app start: http://localhost:31043/index.html?token=HELLO
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: ## (DEBUG)[virtual void Timer::start(int, bool)] Starting timer: [this=0xaaab0162ccd0] [destroy=0]
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: ...parse_config...
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: Failed to convert: '' (err=bad lexical cast: source type value could not be interpreted as target)
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: bool readJsonFromFile(const string&, Json::Value&): Failed to open file /etc/wam/com.webos.wam.json
Jul 10 18:09:14 m3ulcb afbd-webapps-youtube@1.0[3796]: [0710/180914.967343:ERROR:zygote_host_impl_linux.cc(89)] Running as root without --no-sandbox is not supported. See https://crbug.com/638180.